From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759519AbZCCACc (ORCPT ); Mon, 2 Mar 2009 19:02:32 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759263AbZCCAB4 (ORCPT ); Mon, 2 Mar 2009 19:01:56 -0500 Received: from tomts10.bellnexxia.net ([209.226.175.54]:60820 "EHLO tomts10-srv.bellnexxia.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758158AbZCCABy (ORCPT ); Mon, 2 Mar 2009 19:01:54 -0500 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AhwFABsBrElMQW1W/2dsb2JhbACBWdNYhAYG Date: Mon, 2 Mar 2009 19:01:51 -0500 From: Mathieu Desnoyers To: Ingo Molnar Cc: Masami Hiramatsu , Andrew Morton , Nick Piggin , Steven Rostedt , Andi Kleen , linux-kernel@vger.kernel.org, Thomas Gleixner , Peter Zijlstra , Frederic Weisbecker , Linus Torvalds , Arjan van de Ven , Rusty Russell , "H. Peter Anvin" , Steven Rostedt Subject: [PATCH] Text Edit Lock - kprobes architecture independent support Message-ID: <20090303000151.GD3906@Krystal> References: <20090227185316.GA19811@Krystal> <49A853CD.3020607@redhat.com> <49AC10E9.1090102@redhat.com> <20090302171914.GB21735@Krystal> <49AC5A87.7000604@redhat.com> <20090302222254.GA31962@elte.hu> <49AC63FA.70801@redhat.com> <20090302230915.GA11626@elte.hu> <49AC6DEA.2050304@redhat.com> <20090302234910.GA17956@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline In-Reply-To: <20090302234910.GA17956@elte.hu> X-Editor: vi X-Info: http://krystal.dyndns.org:8080 X-Operating-System: Linux/2.6.21.3-grsec (i686) X-Uptime: 19:00:55 up 2 days, 20:27, 3 users, load average: 0.76, 0.67, 0.60 User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Use the mutual exclusion provided by the text edit lock in the kprobes code. It allows coherent manipulation of the kernel code by other subsystems. Changelog: Move the kernel_text_lock/unlock out of the for loops. (applies on 2.6.29-rc6) Signed-off-by: Mathieu Desnoyers Acked-by: Ananth N Mavinakayanahalli CC: ananth@in.ibm.com CC: anil.s.keshavamurthy@intel.com CC: davem@davemloft.net CC: Roel Kluin <12o3l@tiscali.nl> --- kernel/kprobes.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) Index: linux-2.6-lttng/kernel/kprobes.c =================================================================== --- linux-2.6-lttng.orig/kernel/kprobes.c 2009-01-30 10:24:45.000000000 -0500 +++ linux-2.6-lttng/kernel/kprobes.c 2009-01-30 10:27:56.000000000 -0500 @@ -43,6 +43,7 @@ #include #include #include +#include #include #include @@ -699,9 +700,10 @@ int __kprobes register_kprobe(struct kpr goto out; } + kernel_text_lock(); ret = arch_prepare_kprobe(p); if (ret) - goto out; + goto out_unlock_text; INIT_HLIST_NODE(&p->hlist); hlist_add_head_rcu(&p->hlist, @@ -709,7 +711,8 @@ int __kprobes register_kprobe(struct kpr if (kprobe_enabled) arch_arm_kprobe(p); - +out_unlock_text: + kernel_text_unlock(); out: mutex_unlock(&kprobe_mutex); @@ -746,8 +749,11 @@ valid_p: * enabled and not gone - otherwise, the breakpoint would * already have been removed. We save on flushing icache. */ - if (kprobe_enabled && !kprobe_gone(old_p)) + if (kprobe_enabled && !kprobe_gone(old_p)) { + kernel_text_lock(); arch_disarm_kprobe(p); + kernel_text_unlock(); + } hlist_del_rcu(&old_p->hlist); } else { if (p->break_handler && !kprobe_gone(p)) @@ -918,7 +924,6 @@ static int __kprobes pre_handler_kretpro } arch_prepare_kretprobe(ri, regs); - /* XXX(hch): why is there no hlist_move_head? */ INIT_HLIST_NODE(&ri->hlist); kretprobe_table_lock(hash, &flags); @@ -1280,12 +1285,14 @@ static void __kprobes enable_all_kprobes if (kprobe_enabled) goto already_enabled; + kernel_text_lock(); for (i = 0; i < KPROBE_TABLE_SIZE; i++) { head = &kprobe_table[i]; hlist_for_each_entry_rcu(p, node, head, hlist) if (!kprobe_gone(p)) arch_arm_kprobe(p); } + kernel_text_unlock(); kprobe_enabled = true; printk(KERN_INFO "Kprobes globally enabled\n"); @@ -1310,6 +1317,7 @@ static void __kprobes disable_all_kprobe kprobe_enabled = false; printk(KERN_INFO "Kprobes globally disabled\n"); + kernel_text_lock(); for (i = 0; i < KPROBE_TABLE_SIZE; i++) { head = &kprobe_table[i]; hlist_for_each_entry_rcu(p, node, head, hlist) { @@ -1317,6 +1325,7 @@ static void __kprobes disable_all_kprobe arch_disarm_kprobe(p); } } + kernel_text_unlock(); mutex_unlock(&kprobe_mutex); /* Allow all currently running kprobes to complete */ -- Mathieu Desnoyers OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68